The technology of the present disclosure relates to a fixing device and an image forming apparatus including the same.
In general, an image forming apparatus, such as a laser printer, is provided with a fixing device in order to fix a toner image, which has been transferred to a paper, to the paper. The fixing device has a heating roller and a pressing roller, and is configured to heat the toner image and fix the toner image to the paper while the paper is passing through between the both rollers.
This type of fixing device, typically, has a temperature sensor for detecting the surface temperature of the heating roller. Furthermore, on the basis of the temperature detected by the temperature sensor, the fixing device controls the surface temperature of the heating roller to a fixing temperature. As the aforementioned temperature sensor, a contact type temperature sensor contacting with the heating roller and a non-contact type temperature sensor not contacting with the heating roller have been known. Since the non-contact type temperature sensor does not contact with the surface of the heating roller, the surface of the heating roller is hardly damaged. Therefore, in recent years, there have been proposed various fixing devices provided with the non-contact type temperature sensor.
In addition, there is also a case in which an endless belt is wound around the heating roller, and a toner image is heated and is fixed to a paper while the paper is passing through between the endless belt and the pressing roller. In this case, the surface temperature of the endless belt is detected by the temperature sensor.